E 321 ] 
ufual wooden cover, to prevent any dub from falling 
into the quickfilver. In fuch a tube the friction is 
much lefs 5 and I can obferve the mod; fudden change 
in the weather, even to an 80 part of an inch ; tho’ 
in my journal I only fet down a 40 part. For ex- 
ample, March 12, 1752 , at night, 29 14a-, is 29 
inches 14-j twentieth parts and a half of an inch, or 
t§ parts. I am, 
Dear Sir, 
Your mob humble fervant, 
James Simon, 
S f 
A TABLE. 
